Accelerated cardiovascular flow MRI

4D flow magnetic resonance imaging (MRI) can quantify and visualize complex blood flow in the heart and the arteries. The main disadvantage of 4D flow MRI is a very long acquisition time of up to 30 mins, which is typically addressed by sampling less data or by reducing the temporal resolution of the scan. If less data is sampled, the MRI images need to be reconstructed with advanced algorithms such as a compressed sensing (CS) algorithm, to maintain the image quality of a regular scan. In this thesis a new CS acquisition and reconstruction technique is presented that enables high temporal resolution 2D flow MRI for regional pulse wave velocity (PWV) estimation as well as fast 4D flow MRI with scan times of only 4 mins. To demonstrate the accuracy of fast 4D flow MRI, the effect of acceleration on velocity and wall shear stress (WSS) was investigated in the carotid arteries and the aorta. In a clinical study, PWV, vessel wall thickness (WT) and WSS in 43 patients with familial hypercholesterolemia and 18 unaffected siblings was investigated using 2D and 4D flow MRI. In addition to the MRI sequence development, in this thesis an MRI-compatible isolated beating pig heart model was presented. 4D flow MRI of the working heart provided detailed images of intra-cardiac and coronary flow. These scans were also feasible after aortic valve replacement procedure and offer a broad range of future applications.